[uuilly]

It should be possible to get a best fit curve between all the towers to get a more accurate position.

[iang]

Yep, it's called cell id location. I worked in mobile phone location about 8 years ago and you could find a rough position (about 200m radius IIRC) and we used it as a first pass. That was on GSM networks, 3G cells are smaller.

[metageek]

And the newer E911 requirements which kick in next year call for 100m accuracy.